The present disclosure generally relates to a pallet car for conveying material to be processed through a furnace. More specifically, the present disclosure relates to sidewall members for creating first and second sidewalls of a pallet car that each include a heat-resistant lining to eliminate the need for a hearth layer along the sidewalls.
Straight grate pallet cars are used to transport mineral material, such as iron ore pellets, through a furnace for sintering and oxidizing. The mineral material being processed is carried through the furnace on a series of aligned pallet cars. Each car has a mineral bed that contains the material being processed. FIG. 1 illustrates a pallet car 10 that represents the current state of the art. The pallet car 10 includes a pallet frame 12 that defines a generally horizontal support surface 14. The frame 12 includes a pair of end castings 16 that each support a series of rollers 18 that support the weight of the pallet car 10 during movement of the pallet car through the furnace.
The pallet car 10 includes a first sidewall 20 and a second sidewall 22 that extend along the entire length of the pallet car 10 to support a bed of mineral material 24 to be processed. In the prior art pallet car 10 shown in FIG. 1, both the first and second sidewalls 20, 22 are formed from a lower casting 26 and an upper casting 28. The upper and lower castings are both formed from metallic material and combine to form the first and second sidewalls 20, 22.
Since each of the sidewalls are formed from metal castings, the prior art pallet car 10 utilizes a hearth layer 30 of pre-processed material. The hearth layer 30 extends upward along both the first sidewall 20 and the second sidewall 22 as well as along the top surface of the grate bars 32 supported along the support surface 14 of the frame 12. The hearth layer 30 serves as a heat sink to protect the pallet car sidewall castings 26, 28 from the high temperatures required in the furnace for processing the mineral material 24 into usable product. In the embodiment shown in FIG. 1, the material that needs to be processed is shown by the green pellets 34 which are separated from the sidewall castings 26, 28 and the grate bars 32 by the hearth layer 30. As can be understood in FIG. 1, the total volume of material 24 that needs to be processed in the area shown by 34 is reduced due to the pre-processed material that forms the hearth layer 30. After the material 34 is processed, both the material 34 and the hearth layer 30 are removed from the pallet car 10 and a new hearth layer 30 is created. Thus, the use of the hearth layer 30 reduces the operating efficiency of the furnace due to the re-processing of the material that is required to form the hearth layer 30.